Tubular lamp base and socket



Nov. 15, 1938. A. J. MARSHAUS TUBULAR LAMP BASE AND SOCKET .Filed March25. 1938 59 Inventor: 3y Anthohg J. Mar-shaus,

H s Attorneg.

Patented Nov. 15, 1938 UNITED STATES- mm Lamp Base Ann socxa'r Marshaus,East Cleveland, Ohio, assignor to General Electric Company, a corpo-Anthony J.

ration of New York REISSUED AUG 2 7 1940 App ication March 25, 1938,Serial No. 198,058

a 10 Claims.

My invention relates to electric lamps and similar devices, and moreparticularly to a base and socket construction for such devices. Stillmore particularly, my invention relates to a base and socketconstruction for electric lamps of the double-ended discharge type, inwhich a filamentary electrode is mounted at each end of the lamp. v

One object of my invention is to provide a base and socket constructionfor electric lamps wherein the lamp may be readily inserted in itssocket and positively locked therein so as to eifectively preventunwarranted or premature disengagement therebetween.

Another object of my invention is to provide an electric lamp socket inwhich the contact terminals are entirely concealed and unexposed so thatthe danger of shock or of short circuits is absent. 7

Still another object of my invention is to provide a base and socketconstruction for electric lamps wherein the lamp may be freely rotatedin its socket, thereby eliminating the possibility of the base contactprongs being broken off the base, or the cement bond between the baseand the glass envelope of the lamp being disrupted during insertion inor removal of the lamp from its socket.

A further object of my invention is to provide a lamp base constructionwhich will insure the correct assembly of the lamp in its socket,thereby eliminating the possibility of any binding or Jamming oi thebase in the socket during insertion of the lamp in such socket.

A still further object of my invention is to provide a socket and baseconstruction for electric lamps in which the base is provided with aplurality of pins or prongs arranged in a common plane, and the socketis provided with a circular slot and a diametrical slot with leafsprings disposed in said circular slot on opposite sides of saiddiametrical slot, whereby the lamp base prongs may be inserted in saiddlametrical slot'and the lamp then rotated to bring certain of saidprongs into interlocking engagement with the leaf springs.

Further objects and advantages oi. my invention will appear from thefollowing detailed description of a species thereof and from theaccompanying drawing.

In the drawing, Fig. 1 is a side view, partly in section, of a base andsocket construction comprising my invention, the base being mounted on alamp disposed in correct position preparatory to its insertion in thesocket; Fig. 2 is an isometric view of the socket shown in Fig. 1 withthe cover plate removed and shown separate therefrom: Fig. 3 is an endview, partly in section, of the inner or lamp-engaging end of the socketshown in Fig. 1; Fig. '4 is a detailed view of the cover plate for thesocket shown in Fig. l;-

Referring to the drawing, the socket l0 according to my inventioncomprises a base or body member ii, a pair of spring fingers or contactmembers i2, i2, and a cover plate i3. The base and cover plate membersii and i3 respectively are made of suitable insulating material,preferably that commercially known as Bakelite. The inner orlamp-engaging side it of the base member is hollowed out adjacent itsfront wall it to provide a circular slot l8 forming a cylindrical studi1, and a diametrical slot i8 extending rearwardly from the front wallit back through the cylindrical stud ll. The inner side i4 ofthe basemember is further hollowed out rearwardly of the circular slot i6 toprovide a channel IS in substantial alignment'with the said diametricalslot is and extending rearwardly from the circular slot it to the backof the base member. To provide clearance for flexing of the springcontact members i2, the walls 20 of the channel l9 diverge forwardly. Atits rearmost extremity the channel is is widened or enlarged, asindicated at M, to thereby provide suitable abutment shoulders 22, 22for the spring contact members i2, i2. These abutment shoulderspreferably extend at approximately right angles to the longitudinal axisof the channel IS. The base member'is provided at its rear with a pairof oppositely extending projections 23, 23 having: openings 24 throughwhich socket mounting screws are adapted to extend.

Mounted within thehollowed-out portions i6 and IQ of the base membersare the plate spring elements i2, i2 previously referred to, said springelements constituting the terminal or contact members of the socket.These contact members are preferably made of full-spring phosphorbronze,and are bent laterally at their rear extrmities to provide mountinglugs25 which are securely clamped against the abutment shoulders 22 by aclamping lug '26 extending from the rear of the cover plate l3. The twocontact members are separated from each other by a spacing lug 21provided for that purpose on the the contact members lying in saidchannel. The

width of the spacing lug 21 is preferably such as to clamp the fingerportions 23 against the rear extremities of the forwardly divergingchannel walls 23, 23.

The forward portions of the spring fingers 23 are curved away from eachother to thereby provide arcuate portions 23 extending into the circularslot I6 on opposite sidesof the diametrical slot I3. The arcuateportions 23 are so formed as to be substantially concentric with thecircular slot i6, and are preferably curved on a radius equal to orslightly larger than that of the inner wall 30 of the said circularslot. To provide a definite rotative locked position for the lamp, thearcuate portions 23 of the spring fingers 23 are provided with outwardlyextending diametrically opposite notches 3|, 3| preferably located in aplane extending substantially at right angles to the diametrical slotI3. The forward extremities of the arcuate portions 23 are curledoutwardly, as indicated at 32, and preferably terminate adjacent theplane of the walls of the diametrical slot l3 so as not to obstruct thesame.

The hollowed-out side of the base member H is covered by the previouslymentioned cover plate i3 which is secured to the base member by means ofrivets 33, preferably of soft brass, embedded in the molded material ofthe base member and extending through' properly located openings 34 inthe cover plate. The side wall it of the base member is preferablyrecessed an amount equal to the thickness of the cover plate to form arecessed mounting seat 35 therefor, thus providing a flush mounting forthe cover plate. A circular opening 36, concentric with the circularslot it in the base member, is provided in the cover plate l3, as wellas a slot 31 in alignment with and of the same width as the diametricalslot i3 in the base member. The slot 31 extends from the front of thecover plate back to the circular opening 36, thus providing a passagewaythereinto.

As before described, the cover plate 13 is formed at its rear extremitywith a clamping lug- 26 which extends into the widened recess 2| at therear of the base member and clamps the mounting lug 25 on each springcontact member [2 against its co-operating abutment shoulder 22 on thebase member. In addition, the cover plate is further provided with thepreviously referred to spacing lug 21 which extends into the channel l3in the base member and maintains the spring contact members l2, I! inspaced relation. Circuit connections to the contact members of thesocket are made by means of wire leads 38, 33 soldered to the fingerportions 23 of the contact members closelyadjacent the bottom wall ofthe channel l3, and extending out through channels or grooves 33, 33provided for that purpose in the clamping lug 23 on the cover plate.

The lamp base 40 for co-operation with the above-described socket l0comprises a cup-shaped body of suitable insulating material preferablyof Bakelite and consisting of a bottom or end wall 4| and a cylindricalwall 42. The cylindrical wall is of the proper internal diameter to fitloosely over the end or neck portion 44 of the glass envelope 45 of thelamp 43, to which neck portion the base is united by suitable cement 46.The base 431s provided with three outwardly extending equally spaced,and aligned prongs or pins 41 mounted in the end wall 4| of the base andextending therethrough. However, if desired, the center pin may beomitted and only the two outer pins employed. While not necessary, thepins 41are preferably mounted in a common plane extending radiallythrough the axis of the cylindrical base. The said pins 41 are hollowand are preferably made of brass and nickel plated. To control theextent to their outward projection, which should be slightly less thanthe total depth of the pin slots in the socket ill, the pins areprovided with an annular locating' shoulder 43 intermediate their ends.The

pins may be secured to the end wall 4| of the base either by beingmolded therein, or by staking, in which the inner edges of the pins arerolled or peaned over onto the inner or rear surface of the end wall 4|.The lamp lead wires 43, 43 extend into the hollow outer pins or prongs41 and are soldered therein, preferably by dipping the hollow open-endedpins in a bath of molten solder.

Where the base and socket construction com.- prising my invention is tobe used for mounting a double-ended lamp such as a fluorescent dischargetube, as shown at 43 in Fig. 1, a base 40 is mounted on each end of thelamp in such a way that alL of the pins or prongs 41 lie in a commonplane. The filamentary electrode 50 at each end of the lamp is connectedby the lead wires 43 to the two outer pins 41 of the adjacent base 40,leaving the center pin in each base as a dummy pin. A pair of socketsl3, l3 constructed in accordance with my invention are mounted on asuitable fixture 5| so as to be in alignment with each other. Thesockets should be spaced the proper amount from each other to therebyfreely receive the lamp 43 therebetween. The sockets are accordinglyspaced so that the distance between the opposing or facing surfaces l4,I4 is slightly greater than the length of the lamp 43- exclusive of theprojecting pins or prongs 41. The socket lead wires 33, 33 extendthrough openings in the mounting wall 52 of the fixture BI and areconnected to suitable starting and operating apparatus which may bemounted, if desired, in the fixture.

To insert the lamp as m the sockets no, lo, the

lamp is first placed in the position shown in Fig. 1 with the pins 41 inalignment with the diametrical pin slots l3 and 31 in the sockets. Thelamp is then inserted between the sockets by a straight inward movement,the pins 41 at each end of the lamp being guided at the same time intothe cooperating diametrical pin slots in the sockets. The inwardmovement of the lamp is continued until the two outer pins at each endof the lamp are brought into alignment with, and the center or dummy pincoincides with the center of the circular slot IS in the socket basemember Ii. To so align the outer base pins 41 with the said circularslot, the circular opening 33 in the socket cover plate I3 is made ofthe same diameter as, or slightly greater than the distance d (Fig. 1)between the outer sides of the two outer base pins 41. Thus, thatportion 53 of the wall of the circular opening 36 opposite or in linewith the diametrical pin slot 31 constitutes a stop for limiting theinward movement of the lamp and simultaneously aligning the outer basepins with the circular pin slots IS in each socket. The center or dummypin at each end of the lamp inof the proper internal face of theBakelite disc 5'! 2,187,174 the first pin inserted cannot be jammed intothe front portion of the circular pin slot It when moved into alignmenttherewith.

Whe the outer base pins at each end of the lamp ave been moved intoalignment with the circular pin slot I I in each socket. as describedabove, the lamp may then be readily rotated in either direction againstthe spring resistance of the contact members I! in each socket. Byrotating the lamp in either direction, the two outer pins or prongs I!in each base will engage the arcuate portions "of the spring contactmembers i2 and so flex the said members. when the lamp has been rotatedapproximately ninety degrees, the two outer base pins at each end of thelamp will be brought into alignment with, and will become locked in thenotches II in the spring contact members if, thereby providing apositive lock against unwarranted or premature disengagement of the lampfrom the sockets. Thus where the lamp is to be mounted on a ceiling, soas to occupy an inverted position, there is no danger whatever of thelamp accidentally falling out of the sockets. During the above describedrotation of the lamp in the sockets i0. iii, the center or dummy pins ateach end of the lamp co-operate with the diametrical pin slot walls tothereby fix the axis of lamp rotation in a direction transversely ofsaid diametrical slots.

In the modified form of lamp base shown in Fig. 7, the body portionthereof comprises a cylindrical metallic collar It provided with aninwardly extending end flange II forming a part of the base end wall.The collar 54 with its flange 55 is preferably punched as a unit fromsheet brass, and is preferably nickel plated. The flange 55 is ofuniform inward extent so as to thereby provide a centrally locatedcircular opening 58 in the base end wall. This opening I! is closed by adisc 51 of insulating material, preferably Bakelite, which is molded tothe ofl'set edge 58 of the flange 55 so as to lie flush with the outersurface of said flange. The desired number of base pins 41 (i. e.,either two or three) are mounted in the Bakelite disc 51 in the samemanner as in the previous form of base. The inner suris formed with acentrally located circular recess is for the purpose of accommodatingtherein the exhaust tip of the lamp bulb. 'I'he brass cylindrical collar54 is diameter to flt loosely over the neck portion 44 of the glass lampenvelope-l5,

' and it is secured thereto in the same manner as before, i. e., bysuitable cement ll.

The use of abrass collar 54 to encircle the neck portion 44 of the glasslamp envelope 5 obviates any danger of breakage of s the contraction ofshrinkage of the encircling collar or band of the base upon cooling,following the base cementing operation. In addition, the use of therelatively thin brass collar 54 together with the centrally locatedBakelite disc 5! permits closer mounting of the base to the end'of the75 the socket in may be somewhat widened and: the

lamp envelope 45 since the said disc 51 can extend into the recess inthe end of the envelope provided by the stem tube flare. The result ofsuch a closer mounting is to reduce the longitudinal extent of thedarkened or unillumlnated portions at each end of the lamp duringoperation, occasioned by the presence of a base thereat. This isparticularly advantageous in cases where a series of lamps 43 are tobe'mounted in alignment with one another so as to approximate acontinuous line of light. In ,this connection,

'bers mounted within said neck portion by- 3 opposite faces eachprovided with a pair of contact members l2, I! thus 1011111118, inenact, a

double socket for mounting two lamps 43 end to end and. in axialalignment to thereby approximate a continuous line of light.

From the above description, it is evident that I have providedan.improved base and socket construction for the mounting of electriclamps and similar devices, pe. whereby the same may be positively lockedin said sockets to guard against unwarranted disengagement therefrom.Furthermore, the contact members of my improved socket are wellconcealed by the cover plate thereof so as to prevent short circuitstherebetween as well as iniurious shocks therefrom.

What I .claim as new and desire to secure by Letters Patent of theUnited States is:

l. A socket for electric lamps and similar devices comprising a memberof insulating material, said member being provided in a face thereofwith diametrically opposite arcuate slots and also with a slot extendingdiametrically of and intersecting both of said arcuate slots, saiddiametrical slot extending'to an edge of said face, and spring contactmembers mounted in'sald member adjacent said arcuate slots and onopposite sides of said diametrical slot.

2. A socket for electric lamps and similar devices comprislng a memberof insulating material, said member being provided in'a face thereofwith diametrically opposite arcuate slots and also with a slot extendingdiametrically of and intersecting both of said arcuate slots, saiddiametrical slot extending tov an edge of said face, and spring contactmembers mounted in said member adjacent said arcuate slots and on.opposite sides of said diametrical slot, said contact members beingprovided notches. a v

3. A socket for electric lamps and similar devices comprising a memberof insulating material, said member being provided in a face thereofwith a circular slot and 'also with a slot extending diametrically ofsaid cireular slot and continuing to an edge of said face, and springcontact memsaid circular slot on oppoparticularly of the double-endedwith diametrically opposite lo I site sides of said diametrical slot,said contact of with a circular slot and also with a slot extendingdiametrically of said circular slot and continuing to an edge of saidface. and spring contact members mounted within said member and havingarcuate portions disposed in said circular slot on opposite sides ofsaid diametrical slot, said with the inner wall of said circular slot.

5. A socket for electric lamps and similar devices comprising-a memberof insulating material. said member being provided in a face thereofwith a circular slot and also with a .slot extending diametrically ofsaid circular slot and continuing to an edge of said face, and springcontact members mounted within said member and having arcuate portionsdisposed in said circular slot on opposite sides of said diametricalslot, said arouate portions being substantially concentric with theinner wall of said circular slot and having diametrically oppositenotches disposed in a arcuate portions being substantially concentric 4.plane extending substantially transversely of said diametrical slot. I

6. A socket for electric lamps and similar devices comprising a basemember of insulating material, said base member being provided in a facethereof with a circular slot and also with a slot extendingdiametrically of said circular slot and provided with a continuing to anedge of said face. spring contact members mounted within said basemember and having arcuate portions disposed in said circular slot onopposite sides of said diametrical slot, said arcuate portions beingsubstantially concentric with the inner wall of said circular slot, anda cover plate of insulating material secured to said base member, saidcover plate being provided with a circular opening concentric with saidcircular slot and of a diameter slightly larger than that of saidarcuate portions and also being slot in alignment with saiddiametricalslot and extending to the edge of said cover plate.

7. In combination, an electric device provided with a base having aplurality of aligned pins extending outwardly therefrom, and a socketfor co-operation therewith, said socket comprising a member ofinsulating material having diametrically opposite arcuate slots and aslot extending diametrically of and intersecting both of said arcuateslots, said diametrical slot extending to an edge of said member, andspring contact members mounted within said arcuate slots on oppositesides of said diametrical slot and constructed and arranged to engagecertain of said pins upon their rotation in said arcuate slots.

8. In combination, a double-ended electric device having a base at eachend, each of said bases having a plurality of aligned pins extendingoutwardly therefrom, all of said pins lying in a common plane, and apair of spaced opposed sockets constructed and arranged to receive andmount the said .electric device therebetween, the opposing faces of saidsockets being provided with circular pin slots and aligned straight pinslots extending diametrically of said circular slots and continuing tothe front edge of said faces, said sockets also having spring contactmembers mounted in said circular slots on opposite sides of saiddiametrical slots and constructed and arranged to engage certain of saidpins upon their 50 rotation in said arcuate slots.

mam-r4.

9. In combination, a double-ended electric device having a base at eachend. each of said bases having a plurality of aligned pins extendingoutwardly therefrom, all of said pins lying in a common plane, and apair of spaced opposed sockets constructed and arranged to receive andmount the said electric device therebetween, said sockets being providedwith opposing circular pin slots having diametrically opposite springcontact members therein, said sockets also having aligned straight pinslots extending rearwardly from the front edge thereof and,diametrically intersecting said circular slots whereby the said electricdevice may be mounted in said sockets by insertion of the pins at eachend of the device in the said straight pin slots in the adjacent socketfollowed by straight rearward movement of said device until the outerpins of each base are brought into alignment with the said circularslots whence the device may then be rotated in either direction tothereby bring the said outer pins into engagement with said contactmembers.

10. In combination, a double-ended electric device having a base at eachend, each of said bases having a plurality of aligned pins extendingoutwardly therefrom, all of said pins lying. in a common plane, and apair of spaced opposed sockets constructed and arranged to receive andmount the said electric device therebetween, said sockets being providedwith opposing circular pin slots having diametrically opposite springcontact members therein, the spring contact members in each socket beingprovided with diametrically opposite notches, said sockets also havingaligned straight pin slots extending rearwardly from the front edgethereof and diametrically intersecting said circular slots whereby thesaid electric device may be mounted in said sockets by insertion of thepins at each end of the device in the said straight pin slots in theadjacent socket followed by straight rearward movement of said deviceuntil the outer pins of each base' are brought into alignment with thesaid circular slots whence the device may then be rotated in eitherdirection to thereby bring the said outer pins into interlockingengagement with the said notches in said contact members.

J. MARSHAUS.

